22 



A.R. MEAD 



evert together as a unit, forming a quite different intromittent 

 organ. The very shell characters that seemed to link these five 

 species with Callistoplepa now are seen conchologically to 

 distinguish the more primitive genus Bequaertina from Acha- 

 tina s.s. 



On the basis of somewhat overlapping shell characters, 

 available distributional records, and the limited anatomical 

 evidence, the species of Bequaertina break into two groups: 

 (1) the malleate, mammillate B. fraterculus (Dupuis & 

 Putzeys, 1900) and B. graueri, and (2) the cancellate B. 

 pellucida, B. marteli and B. pintoi. B. pellucida of southeast 

 Zaire, close to what is believed to be its ancestral home, is 

 plesiomorphic within the group and stands between an ances- 

 tral achatinid stock of the Zaire Basin and Achatina s.s., 

 which today is largely restricted to that basin. A branch of the 

 ancestral stock moved north and northeast to give rise to the 

 apomorphic B. fraterculus and B. graueri. A more conserva- 

 tive second branch moved east to give rise to B. pellucida and 



B. marteli. This second branch continued further east and 

 then into a strong north-south axis to give rise to the closely 

 related B. pintoi. The known distribution of the genus (Fig. 

 16) embraces a vast area of the Rift Valley - Lake Region and 

 the Lualaba branch of the Zaire River in central, eastern and 

 southeastern Africa. Greater field collecting will probably 

 extend the limited distributions of B. fraterculus and B. 

 marteli. 



Pilsbry & Cockerell (1933), on the erroneous assumption 

 that Achatina graueri 'represented an intrusion of a South 

 African type into the Central African region', initially 

 decided to place it in the genus Cochlitoma. They softened 

 their stand on the advice of M. Connolly and designated it 

 'Achatina (Cochlitoma) graueri'. However, this species can- 

 not possibly be considered congeneric with Cochlitoma zebra 

 (Bruguiere, 1789), which Pilsbry (1904:xiii, 78) selected as 

 the type species of the genus Cochlitoma, because Mead 

 (1992) shows Achatina zebra anatomically belongs to subge- 

 nus Tholachatina of Archachatina. Since the present group of 

 five species is not congeneric with the species in either 

 Callistoplepa or Achatina s.s., and since this group also is not 

 congeneric with Achatina hortensiae Morelet, 1866, which 

 Pilsbry (1904:21) selected as the 'type' of Serpaea, there is no 

 other available genus-group name. Ganomidos cannot be 

 considered because it is a junior subjective synonym of 

 Callistoplepa. For these reasons, the generic name Bequaer- 

 tina is proposed. It is named in honour of the late Dr Joseph 



C. Bequaert, Agassiz Professor of Zoology at Harvard Uni- 

 versity, who will remain the classical authority not only in the 

 Achatinidae, but also in several families of insects and 

 arachnids that he mastered in his long lifetime. Because B. 

 graueri is the largest and most conspicuous of the five species, 

 and because it has departed farthest from what is believed to 

 be the ancestral stock, it is here selected as type species of the 

 genus. 



Early in the present study, it became obvious that this 

 group of five species anatomically was not congeneric with 

 Callistoplepa. This information was shared with colleagues 

 who considerately referred to this new genus in general terms 

 (van Bruggen, 1978:912, 921, 1988:10; van Bruggen & 

 Meredith, 1984:161). Also, the present author made refer- 

 ence to this new genus in an earlier manuscript as 'Callis- 

 toplepa s.i: (Mead, 1992). 



Key to Species 



1 Last whorl distinctly granulate above the periphery, or at least 

 in a limited subsutural zone; growth wrinkles conspicuous to 

 dominant 2 



Last whorl faintly granulate, malleate, lirate or smooth except 

 for modest irregular growth wrinkles 4 



2 Apex broadly obtuse; 6 whorls = > 50 mm; yellowish, ochra- 

 ceous or olivaceous; gross granulate sculpture; first nepionic 

 whorl 2-3 mm in diameter; second whorl expanding broadly; 

 sculpture of second whorl coarse and either distinctly granular 

 or depressed and poorly defined; transverse measurement at 

 junction of third and fourth whorls is 2'/2-4 mm; outer lip 

 increasingly arcuate basally; growth wrinkles bold or moder- 

 ately heavy 3 



Apex subacute to narrowly obtuse; 6 whorls = ~ 40 mm, 7 

 whorls = 53-60 mm; translucent dull fulvous to dull olivaceous- 

 brown; moderately coarse to fine granulate sculpture; first 

 nepionic whorl 2 mm in diameter; second whorl tends to be 

 slightly constricted, expanding limitedly; sculpture of second 

 whorl finely engraved, delicate; transverse measurement at 

 junction of third and fourth whorls is 2-2'/:? mm; outer lip evenly 

 arcuate; growth wrinkles thin, of modest calibre. Southeast 

 Zaire, northeast Zambia and west central Tanzania . pellucida 



3 Last whorl large, rarely strikingly so; ground colour intense 

 olivaceous-yellow to subdued olivaceous; prominent closely 

 aligned somewhat irregular costate transverse ridges embrace 

 the gross elongate granules with bold vertical emphasis, domi- 

 nating the spiral lines; strongly contrasting zigzag castaneous 

 flammules usually present, pale unicolorous forms uncommon; 

 first nepionic whorl 2V2-3 mm in diameter; sculpture of second 

 whorl coarse, granular, elevated, tightly packed; transverse 

 measurement at junction of third and fourth whorls is 3-4 mm; 

 third whorl deeply and grossly granulate. Middle west and east 

 shores of Lake Tanganyika, Zaire and Tanzania marteli 



- Last whorl large, often very large to ventricose; ground colour 

 dark olivaceous to pale olivaceous yellow; coarse granulate 

 sculpture above periphery, reduced or absent below periphery 

 (varies within a single whorl); transverse ridges moderate, 

 slender, fairly uniform, in balance with the spiral lines, con- 

 spicuous below periphery but obscured by granulate sculpture 

 above periphery; usually unicolorous, but narrow fairly straight 

 light castaneous stripes may be present; first nepionic whorl 

 2-2'/2 mm in diameter; sculpture of second whorl coarse, but 

 superficial, vaguely and irregularly impressed, patchy, poorly 

 defined, often worn smooth; transverse measurement at junc- 

 tion of third and fourth whorls is 2V2-3 mm; third whorl 

 delicately to moderately granulate. East Africa, almost reaching 

 the Limpopo River in the south (4-20° S, 27-39° E) pintoi 



4 Apex of shell obtuse and noticeably mammillate; shell conspicu- 

 ously to obscurely malleate; opaque or dark and translucent, 

 uniformly or somewhat variably brown or yellow-brown, band- 

 ing limited and irregular; coarse growth wrinkles or extremely 

 fine lirae dominate the sculpture, 6 whorls = > 43 mm 5 



Apex of shell subacute to narrowly obtuse, somewhat elevated 

 but not mammillate; shell not malleate; translucent dull fulvous 

 to dull olivaceous-brown, usually with moderately broad casta- 

 neous flames and stripes irregularly distributed, but may be pale 

 unicolorous; very fine granulate-cancellate sculpture dominates; 

 6 whorls = < 43 mm. Southeast Zaire, northeast Zambia and 

 west central Tanzania pellucida 



5 Shell large (6'A whorls = 60-80 mm), thin but substantial, 

 essentially opaque; usually conspicuously malleate; not cari- 

 nate; growth wrinkles prominent, rather regular; lirae of fifth 

 whorl distinctly transacted by spiral striae; unicolorous or 



